« Crowd-Source Prediction of Mean September Sea Ice Extent (July update) | Main | On persistent cyclones »


Feed You can follow this conversation by subscribing to the comment feed for this post.

Jai Mitchell

I think that we won't really have a good idea what the storm has done to the poles until the next PIOMAS update comes out. If Piomas remains fairly steady in July then we will exceed the 2012 levels, possibly by a very large margin.

However, I think that we have experienced significant fram transport already, that the quality of the ice has degraded significantly and the only reason that we have such a large sea ice area now is because low quality/broken/slushy ice has been spread out by the storm.

In that event then we will see mid CAB ice loss and an effective doubling of pack ice edge surface for increased exposure to the air and water melt.

So I said 2.8 but that comes with a +/- of 1.6/1.0



Is that open water on the right side? Looks like we have a beach-side view now. This says something about the state at the pole. Sun is out as well...

Account Deleted

2.0 M km2. To melt something, grind it and then heat it, rather than heat it and then grind it. The second worked for last year, why should the first not work for this. And please, North Pole out of the ice, big news and big concern.


I have the impression that the discussions on the Forum are more balanced than the ones we are seeing in the crowd-source prediction thread.

There is a tendency for posting very low estimates, far below the levels of 2007 (4.30) and 2011 (4.63) even when area and volume are currently lagging behind 2011.

It seems to me that there is a big focus on the positive feedbacks (like spreading and lack of MYI) while the negative feedbacks are mainly ignored.

Kevin O'Neill

The statistical approach has been the best predictor of September SIE. So, if one simply followed the 'best' approach one would predict something lower than 2012. Any prediction larger than 2012 is ignoring the 'best' predictor available.

Obviously just because the overall trend is downward doesn't mean any individual year cannot increase. But predicting that increase (or a decrease larger than trend) gets into more gut feeling, WAGs, or a framework that includes whatever insights we *believe* we know.

Personally, I basically disregard anything that happened before 2006. To include trends and data before then seems like comparing apples and oranges. I also put more stock in volume trends than SIE or SIA trends. Ice is not 2-dimensional and we can be quickly led astray by forgetting that. But we don't have quick access to daily volume numbers the way we do SIE and SIA.

It's easy to question yourself. A few days or a week of numbers that don't go the way you expected can undermine your confidence in your understanding. It is well to remember that at this time of year the arctic can turn on a dime. Area and extent measures are prone to large errors - especially in the last 10 days of June and the first 10 days of July.

Take a deep breath and try not to get too excited until mid-July; then look at the SIE and SIA numbers and see where they sit. Only then will an extra-ordinary 'cold' summer become apparent. The big melt-out years -- 2007, 2010, 2011 & 2012 -- all crossed the CT SIA 6 Mkm^2 mark on day 191 +/- 1 day. But even these 4 years show a final difference in CT SIA of almost 1 Mkm^2. They really don't begin to seriously diverge until *after* day 211 (August 1st).

And since we're really in a new arctic, there's not even any guarantee that these relatively new patterns will hold true.

Personally, I think predictions below 2 Mkm^2 are *probably* unrealistic; just as I think predictions above 5 Mkm^2 are *probably* unrealistic. But I'm not willing to bet much money either way. I don't see any point in criticizing anyone else's prediction because to do so implies that I *know* what is going to happen. I don't. Of course I believe I'm right and anyone that disagrees with me must be an idiot - but don't we all :)

Susan Anderson

ot alert (but not wholly so):

I am startled to see that central Alaska is currently 91 degrees fahrenheit (a mite under 33 C)



Wow, that's just as warm as it was in Austria today. Luckily, we only have that two weeks at most per year.

Tor Bejnar

Gosh, we in North Florida only have about two weeks per year of 91F maximums. But we also get a couple weeks at 92, a couple at 95 and maybe a week at 100+ (13 weeks worth of 90+ is average, per the statisticians.)


@Tor - problem is transitions that quickly to that heat at those latitudes can be lethal to wildlife. Consider that polar bears have a challenge when it gets much above 5C. Heat isn't where they are typically, but is a tangible threat.

Other species could be hammered as well. It's all about context.

For example, consider what would happen where you are if temps spent a full week with highs hitting 50C? That's about what we're talking about.

Kevin O'Neill

I don't think the University of Tokyo has a SEARCH entry, but they've released a 2013 prediction. They're expecting a 5% decrease from 2012.

Kevin O'Neill

I should have searched a little longer before posting the above - the link is just a brief blurb. The full report can be found here.

2013 Summer Arctic Sea Ice Forecast

Ned Ward

Kevin O'Neill writes: The statistical approach has been the best predictor of September SIE. So, if one simply followed the 'best' approach one would predict something lower than 2012. Any prediction larger than 2012 is ignoring the 'best' predictor available.

I'm not following you. Why does a "statistical approach" have to predict a lower value than 2012?

If you just fit a linear trend to the last decade's September averages, you'd predict that Sept 2013 would average 3.91, well above the 2012 value. There are of course many other choices one could make for a "statistical approach", but lots of them -- including the ones that seem most logical to me -- don't predict a 2013 average that's lower than 2012.

If you look at the full record since 1979, almost half the years show an increase over the previous year. Four of the past ten years did. There's no reason to assume that 2013 must be lower than 2012.

Kevin O'Neill

Ned, a simple linear trend has not been the best predictor. I believe the Gompertz curve is still the best predictor.

Mind you - I'm *not* saying this is the correct approach. But it has been the best predictor so far.

Ned Ward

But, Kevin, according to this a Gompertz curve also predicts that 2013 would be above 2012's mean (see Figure 2). In fact, over the short time span I referred to (the past decade) there's not much difference at all between a Gompertz fit and a simple linear fit.

Again, I see no reason to assume that 2013 will be lower than 2012. The most straightforward statistical methods would predict a bit of a rebound after 2012's abnormally low sea ice extent, and the past month's data from JAXA certainly doesn't contradict that idea.


@ Kevin, Fascinating prediction. Their approach and conclusions seem quite reasonable. They have taken into account the motion and thickness of the ice. I would like to see their model also make use of long term weather predictions, say a 90 day forecast, if any exist, for the arctic. I notice the model is the work of graduate engineering students.

Kevin O'Neill

Ned - I stand corrected - then any estimate other than 3.8 Mkm^2 would be ignoring the best predictor.

My point remains that criticizing others for their predictions amounts to little more than arrogance. It implies that one *knows* what the final result is going to be. None of us *know* what the September SIE mean will be.

Ned Ward

Eh. I don't see anything wrong with commenting on other people's predictions, both in terms of the reasoning used and how closely the results match our own expectations.

True, we don't *know* what the result will be.

But I can certainly generate examples of "better" and "worse" predictions. For example:

(A) "I heard on WUWT that the ice has recovered, so I'm predicting it'll be back to its 1980 level" (i.e., 7.9).

(B) "I compared the PIOMAS volume for this past month in each year (from 2003-2012) to that year's ultimate September NSDIC extent. Based on the most recent volume estimate, I'm predicting this September's extent will be 4.3"

(C) "Based on the alien transmissions I'm receiving through the fillings in my teeth, I predict this September's extent will be 4.3"

I can't speak for anyone else, but I have no problem saying that IMHO (B) is a better prediction than (A). I also have no problem saying that (B) is a better prediction than (C) even though they give the same result.

David Vun Kannon


A report on the recovery of data from the Nimbus 1 satellite that flew Aug-Sep, 1964! It caught the Artic minimum/Antarctic maximum (6.9/19.7 for those not clicking the link) by happenstance.

The story shows how important it is to preserve data for future generations of scientific research. It also makes it especially poignant that these NSIDC archives might close for lack of funding!

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.


Post a comment